Panasonic WH-UD05JE5 Service Manual page 220

19.5.31 Compressor Overheating (F20)
Malfunction Decision Conditions:
During operation of cooling and heating, when temperature above 112°C is detected by the compressor tank
temperature sensor.
Malfunction Caused:
1 Faulty compressor tank temperature sensor.
2 2/3 way valve closed.
3 Refrigerant shortage (refrigerant leakage).
4 Clogged expansion valve or strainer.
5 Faulty outdoor unit PCB (main).
6 Faulty compressor.
Abnormality Judgment:
Continue 4 times in 30 minutes.
Troubleshooting:
Check the compressor tank
temperature sensor.
Does it conform to the
sensor characteristic chart?
Yes
Check the 2/3 way valve.
Is the 2/3 way valve closed?
No
Check for gas leakage.
Is the oil oozing out from
the 2/3 way valve?
No
Caution
No
Replace the compressor
tank temperature sensor.
Yes
Open the 2/3 way valve.
- Repair the pipe flare or
Yes
union nuts.
- Reclaim and recharge
refrigerant.
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Check for clogged expansion
valve or strainer.
Is the expansion valve or
strainer clogged (ice formed)?
No
Reclaim and recharge for a
specified amount of fresh refrigerant.
Is abnormality happened
again?
No
220
- Repair expansion valve
Yes
and/or strainer.
- Reclaim and recharge
refrigerant.
- Replace the outdoor unit
Yes
PCB (main).
- Replace the compressor.
Procedure complete.